Abstract
Horse purslane (Trianthema portulacastrum) and purple nutsedge (Cyperus rotundus) are two noxious C4 weeds of maize crop causing extensive yield losses. A two years field experiment was performed to estimate interference of T. portulacastrum and C. rotundus and to evaluate the role of allelopathic water extracts for effective weed management in maize. Five plant water extracts in ten binary combinations were foliar applied in triplicated randomized complete block design. Plots treated with commercial herbicide atrazine and weedy check (control), were also maintained for comparison. The highest density of both weed species was observed at 45 days after sowing (DAS) while weed dry biomass was higher at 60 DAS. Binary combination of sorghum-sunflower depicted greater suppression for weed density, dry biomass and persistence index (88-92% for T. portulacastrum and 65-81% for C. rotundus) as compared with weedy check. This treatment combination has also recorded an enhancement of 125% in crop resistance index, 84% in leaf area index and 41% in crop growth rate at 60-75 DAS thus, leading to 51% improvement in grain yield. Binary combination of sunflower-brassica returned maximum marginal net benefit, while sorghum-maize combination anticipated the peak value for marginal rate of return. Along with the effective weed management and higher yield, sorghum-sunflower documented the maximum net economic benefits among different plant extract combinations therefore, suggesting that exogenous application of sorghum-sunflower extract can be effectively used for controlling these weeds in maize field.